Window structure of a semiconductor laser

Abstract

A window V-channeled substrate inner stripe semiconductor laser includes window regions formed at both ends of a stimulated region. The stimulated region includes a crescent active layer, and each of the window regions includes a plane active layer for transferring the laser beam emitted from the stimulated region to the mirror. An optical guide layer is formed on said crescent and plane active layers in order to ensure a stable operation of the window structure semiconductor laser.

What is claimed is: 
     
       1. In a window structure semiconductor laser comprising: a stimulated region including a crescent active layer; window regions formed at both ends of said stimulated region, each of said window regions including a plane active layer;   a cladding layer formed on one side of said crescent and plane active layers in said stimulated region and said window regions; and   an optical guide layer formed on the other side of said crescent and plane active layers in said stimulated region and said window regions.   
     
     
       2. The window structure semiconductor laser of claim 1, wherein: said stimulated region defines a waveguide width which is narrower than a waveguide width determined by said each of window regions.   
     
     
       3. The window structure semiconductor laser of claim 1, wherein said optical guide layer has a refractive index which is higher than that of said cladding layer and lower than that of said crescent and plane active layers. 
     
     
       4. In a window structure semiconductor laser comprising: a substrate;   a current blocking layer formed on said substrate;   a V-shaped groove formed in said current blocking layer, said V-shaped groove having a medial wider section and narrower sections disposed at both ends lateral to said wider section;   a cladding layer formed on said current blocking layer;   an active layer formed on said cladding layer, said active layer having a crescent portion formed at a position corresponding to said wider section of said V-shaped groove formed in said current blocking layer, and plane portions formed at positions corresponding to said narrower sections of said V-shaped groove formed in said current blocking layer; and   an optical guide layer formed on said active layer, said optical guide layer having a refractive index which is higher than that of said cladding layer and lower than that of said active layer.   
     
     
       5. The window structure semiconductor laser of claim 4, wherein said current blocking layer has thicker sections formed at the positions corresponding to said narrower sections of said V-shaped groove, whereby said cladding layer formed between said current blocking layer and said active layer is separated from said substrate by said current blocking layer at said narrower sections of said V-shaped groove. 
     
     
       6. The window structure semiconductor laser of claim 4, wherein: said substrate comprises a p-GaAs substrate;   said current blocking layer comprises an n-GaAs layer;   said cladding layer comprises a p-GaAlAs layer;   said activelayer comprises a GaAs layer; and   said optical guide layer comprises an n-GaAlAs layer.   
     
     
       7. The window structure semiconductor laser of claim 4, wherein: said substrate comprises a p-GaAs substrate;   said current blocking layer comprises an n-GaAs layer;   said cladding layer comprises a p-GaAlAs layer;   said active layer comprises a GaAlAs layer; and   said optical guide layer comprises an n-GaAlAs layer.   
     
     
       8. The window structure semiconductor laser of claim 7, wherein an AlAs mole fraction of said active layer at said crescent portion is lower than that of said active layer at said plane portion.